DE102021201617A1 - Electric motor for selective operation with at least two different supply voltages and switching device for the electric motor - Google Patents

Abstract

The invention relates to an electric motor (12) with a rotor (40) and a stator (42), the stator (42) having three stator poles (44) and each stator pole (44I, 44", 44III) having an integer multiple of stator teeth (46 ) each having a plurality of windings (48) for driving the rotor (40), the windings (48) of the stator teeth (46) being designed in terms of their type and/or number such that the electric motor (12) has three phases (U, V, W) can be operated either with a first supply voltage (UH), in particular for mains operation, or with at least one second supply voltage (UL) that is significantly different from the first supply voltage (UH), in particular for battery operation proposed that all windings (48) of a stator tooth (46I, 46II) can be connected in series and/or in parallel for operation with the first supply voltage (UH) or the at least one second supply voltage (UL) and that the phases (U, V , W ) can be switched as a star connection or as a delta connection. The invention also relates to a switching device (50) for controlling the windings (48) of the electric motor (12) and an electrical processing device (10) with the electric motor (12) and the switching device (50).

Description

The invention relates to an electric motor for selective operation with a first or at least a second supply voltage and a switching device for switching the windings of the electric motor and an electrical processing device with an electric motor according to the invention and a switching device according to the invention according to the species of the independent claims.

State of the art

Battery-powered processing devices, especially handheld power tools, have increasingly replaced their mains-powered counterparts in recent years, since the battery packs and electric motors have become lighter and more powerful. The so-called electrically commutated (EC) or brushless direct current motors (BLDC) have established themselves here in particular. Despite the light and compact EC motors and the ever more powerful rechargeable batteries or replaceable battery packs, it is often necessary, especially in the high performance classes, to operate the processing equipment over a longer period of time, so that the rechargeable batteries or replaceable battery packs are charged and/or changed relatively frequently Need to become. There is therefore a need for so-called hybrid devices with corresponding electric motors that can be operated both by battery and by mains power.

From the EP 3 316 453 A1 a battery-powered hand tool in the form of a cordless screwdriver is known. The hand-held power tool has a brushless electric motor with a stator and a rotor mounted within the stator so that it can rotate relative to the latter. The stator comprises three windings, each winding being distributed over two opposite stator poles over the circumference of the stator. The three stator windings can be operated in a delta or star connection by means of appropriate switching means.

the US 2019/0229599 A1 discloses a stationary power tool that can be operated either with a first supply voltage, in particular a mains voltage, or with a second supply voltage, in particular a battery voltage. For this purpose, the power tool has two electronic power units, with a first electronic power unit controlling first windings of the electric motor and a second electronic power unit controlling second windings of the electric motor depending on the detected supply voltage for operating an electric motor. The first and second windings differ in particular in their number of turns and/or the wire cross section. It is provided that the stator teeth of the stator poles of the electric motor either carry the first or the second windings alternately or that each stator tooth has a first and a second winding. Furthermore, the possibility of switching between a star and a delta connection is also shown, the first windings being permanently connected to form a star connection and the second windings to be permanently connected to form a delta connection.

It is the object of the invention to provide an electric motor, in particular a brushless DC motor, in which, in contrast to the prior art, all the windings of the stator are used to operate the electric motor with at least two different supply voltages and for operation in a star or delta circuit be able. In addition, the object of the invention is to provide a corresponding switching device for the electric motor.

Advantages of the Invention

The invention is based on an electric motor with a rotor and a stator, the stator having three stator poles and each stator pole having an integer multiple of stator teeth, each with a plurality of windings for driving the rotor. The windings of the stator teeth are designed in terms of their type and/or number in such a way that the electric motor can be supplied over three phases either with a first supply voltage, in particular for mains operation, or with at least one second supply voltage that is significantly different from the first supply voltage, in particular for battery operation. is operable. To solve the task it is provided that all windings of a stator tooth can be connected in series and/or in parallel for operation with the first supply voltage or the at least one second supply voltage and that the phases can be connected as a star connection or as a delta connection. With particular advantage, such an electric motor allows a very universal use of low DC voltages up to high AC voltages in connection with an easy to design and inexpensive power electronics or switching device for wiring the windings of the electric motor. Due to the fact that all windings of the electric motor are always energized for operation with the first and with the at least one second supply voltage, a reduced weight compared to the prior art is possible with a compact and cost-effective design of the electric motor. An optimal Magnetic coupling of the windings to the stator of the electric motor also ensures high effectiveness. The optional connection of the phases as a star or delta connection results, on the one hand, in connection with the star connection, in a significant reduction in the power requirement by a factor of 1.73 per phase or stator pole, which is particularly advantageous when the electric motor starts up, while in high currents and power can be used in the delta connection. The special design of the electric motor according to the invention allows, for example, when operating with a rectified, first supply voltage of 300 V and a second supply voltage of 36 V, a reduction in the necessary windings per stator pole from 8 (≅ 300 V / 36 V) to 4 (≅ 300 V / 36V / 1.73). The term "type of winding" is intended to mean in particular the number of turns, the cross section and/or the material of the winding.

The invention also relates to a switching device for controlling the windings of the electric motor according to the invention, with the switching device being used to switch the windings of the stator teeth of the electric motor for operation with the first or the at least one second supply voltage in series and/or in parallel and also the phases as a star connection or can be switched as a delta connection. Furthermore, the invention relates to an electrical processing device with the electric motor according to the invention and the switching device according to the invention.

In the context of the invention, “electrical processing devices” should be understood to mean, among other things, battery-operated and/or mains-operated machine tools for processing workpieces using an electrically driven insert tool. The electrical processing device can be designed both as a hand-held power tool and as a stationary power tool. In this context, typical machine tools are hand-held or stationary drills, screwdrivers, percussion drills, planers, angle grinders, orbital grinders, polishing machines or the like. Garden and construction equipment driven by an electric motor, such as lawn mowers, lawn trimmers, pruning saws, engine and trench cutters, blowers, robot breaker and excavator or the like also come into consideration as electrical processing equipment. Furthermore, the invention can be applied to three-phase electric motors of household appliances such as vacuum cleaners, mixers, etc. The term electrical processing device can also be understood to mean road and rail vehicles driven by electric motors, as well as aircraft and ships or boats.

“Operation with a first supply voltage” or “mains operation” should be understood to mean, in particular, operation with an alternating current (AC) in the range from approx. 110 to 240 V. For industrial robots, road and rail vehicles as well as airplanes and ships, significantly higher AC voltages of several 1000 V can also be considered. The typical AC voltages are primarily dependent on the country-specific values and the intended use. “Operation with a second supply voltage that is significantly different from the first supply voltage” or “battery operation” should be understood to mean, in particular, operation with a direct voltage (DC) in the range from 3.6 to 180 V. But even here, significantly higher battery voltages of several 100 V can be considered for vehicles, airplanes and ships. The DC voltage values are primarily based on the typical cell voltages of Li-ion cells. However, other cell voltages are also possible, for example for pouch cells and/or cells with a different electrochemical composition. It should also be noted that the term "significantly different supply voltage" can refer not only to the amplitude but also to the frequency of the supply voltage. Both replaceable exchangeable battery packs and permanently integrated batteries with any number of battery cells can be considered for battery operation. The exchangeable battery packs can be detachably connected to the electrical processing device in a non-positive and/or positive manner via suitably designed electromechanical interfaces. A "releasable connection" is to be understood in particular as a connection that can be released and produced without tools, ie by hand. Since the person skilled in the art is sufficiently familiar with such rechargeable batteries and exchangeable rechargeable battery packs as well as the corresponding electromechanical interfaces, they will not be discussed in any further detail. The terms rechargeable battery, rechargeable battery pack and exchangeable rechargeable battery pack are to be understood below as synonyms, since they have the same meaning for the invention.

In a further embodiment of the invention, it is provided that, for operation with the first supply voltage, all the windings of a stator pole are connected in parallel and the phases are connected in a delta circuit. Alternatively or additionally, it is provided that for operation with the at least one second supply voltage, all the windings of a stator pole are connected in series and the phases are connected in a star connection. In order to always energize all windings of the stator at the same time, the electric motor can be used with optimum utilization of the installation space and a minimum number of windings with a star connection of the phases for the first supply voltage and with a delta connection tion of the phases for the at least one second supply voltage are operated.

The number of windings of a stator pole of the electric motor is essentially dependent on the ratio of the first to the at least one second supply voltage. With a first supply voltage, in particular a mains voltage of, for example, 230 V AC, which typically corresponds to 300 V rectified, and a second supply voltage, in particular a battery voltage, of, for example, 36 V, this results in a number of 8 windings per stator pole, which with two stator teeth 4 windings per stator tooth. With particular advantage, this number can be further reduced by a factor of 1.73 (root 3) in the case of a star connection of the phases, so that only two windings are then required per stator tooth for the same voltage ratio.

In a development of the invention, it is provided that the electric motor can be operated with substantially the same maximum power when the windings are switched between operation with the first and the at least one second supply voltage both with phases connected in a star connection and with phases connected in a delta connection.

Furthermore, it is provided that the switching device according to the invention has a plurality of first switching elements for series connection of the windings of the stator teeth and a plurality of second switching elements for parallel connection of the windings of the stator teeth. For each stator pole with M stator teeth and N windings per stator tooth, M*N-1 first switching elements are provided for series connection and M*(2N-1) second switching elements for parallel connection of the total of M*N stator windings. In a three-phase stator with three stator poles, M=2 stator teeth per stator pole and N=2 windings per stator tooth, this results in 2*2−1=3 first and 2*(4−1)=6 second switching elements per stator pole. The switching device therefore has a total of 3*9=27 first and second switching elements. For the series connection of the windings, the first switching elements of the switching device are closed and the second switching elements are opened, while for the parallel connection of the windings, in the reverse manner, the first switching elements are opened and the second switching elements are closed.

For additional switching of the delta or star connection of the phases, a third and fourth switching element is also provided for each stator pole. The third switching elements are closed and the fourth switching elements are opened for the star connection of the phases, while the third switching elements are opened and the fourth switching elements are closed for the delta connection of the phases. Coming back to the above example of a three-phase electric motor with M=2 stator teeth per stator pole and N=2 windings per stator tooth, this results in a total of 27+6=33 first, second, third and fourth switching elements for the switching device. In order to activate the series connection of the windings in conjunction with a star connection of the phases, all the first and third switching elements are then closed and all the second and fourth switching elements are opened. To activate the parallel connection of the windings in combination with a delta connection of the phases, all second and fourth switching elements are closed and all first and third switching elements are opened. This can be done simultaneously or with particular advantage to avoid short circuits with a dead time between the switching processes.

In order to be able to operate the electric motor in countries with slightly different first supply voltages (for example Japan, Australia, etc.), a further switching element for series connection with a switchable load, in particular a power resistor, is provided for each stator pole. By activating the load, operation with 240 V instead of 230 V or with 120 V instead of 100 V can be implemented very easily.

In a further embodiment, the switching device has additional switching elements for switching a position and/or speed sensor system for the rotor of the electric motor depending on the operation of the electric motor with the first supply voltage or with the at least one second supply voltage. It is thus possible to adapt the position and/or rotational speed sensors in a particularly simple manner to control or regulating electronics or power electronics controlled by them for correct operation of the electric motor.

All switching elements of the switching device can be designed as semiconductor switches, in particular as MOSFETs, field effect transistors, IGBTs, bipolar transistors or the like, or as relays. Depending on the load capacity and switching speed requirements, mixed forms are also conceivable such that, for example, the first and second switching elements are in the form of semiconductor switches and the third and fourth switching elements are in the form of relays.

In order to enable an electric motor that is as compact as possible and easy to replace, the switching device is designed as a modular assembly of the electric motor.

Furthermore, it is provided that the electrical processing device has control or regulating electronics for controlling the switching device. In order to avoid short circuits and to increase operational reliability, it is also provided that the control or regulating electronics switch the first and the second as well as the third and the fourth switching elements with a dead time. In other words, the second and/or fourth switching elements are only closed after the first or third switching elements have been open for the duration of the dead time, so that all switching elements are open for the duration of the dead time. In an analogous manner, the first and/or the third switching elements are only closed after the second or the fourth switching elements have been open for the duration of the dead time. Depending on the switching speed of the switching elements, the dead time can range from a few milliseconds to a few seconds. With increasing technology development in the semiconductor switches, in particular in the MOSFET, IGBT, etc., however, dead times of well under a millisecond in the nanosecond range are also conceivable. In contrast, in the case of an electromechanically designed switching device, the dead times also depend on the switching speed of the operator.

A power bridge for controlling the individual windings of the stator of the electric motor via pulse width modulation (PWM) is connected upstream of the switching device. For this purpose, the power bridge is generally designed as an H-bridge for each phase or each stator pole. The electric motor can be controlled in particular with different speeds and/or torques via the power bridge. However, B6 circuits or the like can also be used as a power bridge.

The switching device, the power bridge and any other electrical components for rectifying, voltage conversion, filtering and/or end interference of the first and the at least one second supply voltage together form power electronics. The term "power electronics" should therefore be understood to mean the part of the electronics that controls the electric motor, which primarily absorbs the winding currents. The power electronics therefore differ from the control and regulation electronics that actuate them. As a rule, the power electronics are installed in the electrical processing device and can thus be specifically adapted to the respective requirements of the device. In this way, over- or under-dimensioning of the power electronics can be avoided. Processing devices with a high energy requirement (e.g. angle grinders, large rotary and demolition hammers, professional kitchen appliances, etc.), for example, have correspondingly powerful power electronics, while processing devices with a rather low energy requirement (e.g. screwdrivers, hand blender, etc.) have cost-effective and significantly less resilient power electronics can be used. In the case of battery-powered devices in particular, complex power electronics, e.g. in the form of a DC/DC converter with a large ratio between the input and output voltage, are then no longer required, resulting in a compact overall drive train.

• • Multispannungsgeräte für Hybrid-Betrieb (Akku- und/oder Netzbetrieb): das elektrische Bearbeitungsgerät kann wahlweise für einen Netzbetrieb mit mehreren ersten Versorgungsspannungen bzw. einer Zwischenspannung und zumindest einer ersten Versorgungsspannung von z.B. 120 V und 230 V und/oder für einen Akkubetrieb mit mehreren zweiten Versorgungsspannungen von z.B. 18 V, 36 V oder 72 V ausgelegt sein.
• • Multispannungsgeräte für Netzbetrieb: das elektrische Bearbeitungsgerät kann für einen Netzbetrieb mit mehreren ersten Versorgungsspannungen bzw. einer Zwischenspannung und zumindest einer ersten Versorgungsspannung von z.B. 120 V und 230 V ausgelegt sein. Somit kann auf den DC-Teil der Leistungselektronik verzichtet werden.
• • Multispannungsgeräte für Akkubetrieb: das elektrische Bearbeitungsgerät kann für einen Akkubetrieb mit mehreren zweiten Versorgungsspannungen von z.B. 18 V, 36 V oder 72 V ausgelegt sein, so dass auf den AC-Teil der Leistungselektronik verzichtet werden kann.
• • Dualspannungsgeräte für Hybrid-Betrieb (Akku- und/oder Netzbetrieb): das elektrische Bearbeitungsgerät kann wahlweise für einen Netzbetrieb mit einer ersten Versorgungsspannung von z.B. 230 V oder für einen Akkubetrieb mit einer zweiten Versorgungsspannung von z.B. 36 V ausgelegt sein. Dies ermöglicht den Einsatz einer einfacheren Leistungselektronik für eine reduzierte Anzahl von Reihen- bzw. Parallelverschaltungen der Wicklungen je Statorpol.
• • Einzelspannungsgeräte für Netzbetrieb, z.B. 230 V.
• • Einzelspannungsgeräte für Akkubetrieb, z.B. 36 V.

The possibility of being able to do without individual components in the electronic processing device, depending on requirements, results in a modular overall concept, in particular from a power bridge, switching device and electric motor for the following applications:

• • Multi-voltage devices for hybrid operation (battery and/or mains operation): the electrical processing device can optionally be used for mains operation with several first supply voltages or an intermediate voltage and at least one first supply voltage of e.g. 120 V and 230 V and/or for battery operation be designed several second supply voltages of 18 V, 36 V or 72 V, for example.
• • Multi-voltage devices for mains operation: the electrical processing device can be designed for mains operation with a plurality of first supply voltages or an intermediate voltage and at least one first supply voltage of, for example, 120 V and 230 V. This means that the DC part of the power electronics can be dispensed with.
• • Multi-voltage devices for battery operation: the electrical processing device can be designed for battery operation with several second supply voltages of eg 18 V, 36 V or 72 V, so that the AC part of the power electronics can be dispensed with.
• • Dual-voltage devices for hybrid operation (battery and/or mains operation): the electrical processing device can be designed either for mains operation with a first supply voltage of, for example, 230 V or for battery operation with a second supply voltage of, for example, 36 V. This enables the use of simpler power electronics for a reduced number of series or parallel connections of the windings per stator pole.
• • Single voltage devices for mains operation, eg 230 V.
• • Single voltage devices for battery operation, e.g. 36 V.

Further options for generating the request signal for switching between the operating modes of the electric motor are described below in the exemplary embodiments.

exemplary embodiments

character list

The invention is based on the 1 until 22 explained by way of example, with the same reference symbols in the figures indicating the same components with the same functionality.

• 1: eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines handgehaltenen Drehschlagschraubers,
• 2: eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemäßen Elektromotors mit einem vier Wicklungen tragenden Statorzahn,
• 3: eine schematische Darstellung eines zweiten Ausführungsbeispiels des erfindungsgemäßen Elektromotors mit einem zwei Wicklungen tragenden Statorzahn,
• 4: ein Schaltbild eines Ausführungsbeispiels des erfindungsgemäßen Elektromotors für eine Parallelschaltung der vier Wicklungen eines Statorpols und eine Dreieckschaltung der drei Phasen des Elektromotors,
• 5: ein Schaltbild eines Ausführungsbeispiels des erfindungsgemäßen Elektromotors für eine Reihenschaltung der vier Wicklungen eines Statorpols und eine Sternschaltung der drei Phasen des Elektromotors,
• 6: ein Blockschalbild eines Ausführungsbeispiels der erfindungsgemäßen Umschaltvorrichtung für den Elektromotor gemäß der 3 bis 5,
• 7: eine Explosionszeichnung des erfindungsgemäßen Elektromotors mit einer erfindungsgemäßen, elektromechanischen Umschaltvorrichtung,
• 8: Ausführungsbeispiele für die erfindungsgemäße, elektromechanische Umschaltvorrichtung mit einem verdrehbar ausgestalteten Träger,
• 9: Ausführungsbeispiele für die erfindungsgemäße, elektromechanische Umschaltvorrichtung mit einem verschiebbar ausgestalteten Träger,
• 10: weitere Ausführungsbeispiele für einen verschiebbaren Träger der erfindungsgemäßen, elektromechanischen Umschaltvorrichtung,
• 11: ein weiteres Ausführungsbeispiel für einen verdrehbaren Träger der erfindungsgemäßen, elektromechanischen Umschaltvorrichtung,
• 12: ein schematisches Blockschaltbild für das erfindungsgemäße elektrische Bearbeitungsgerät,
• 13: eine schematische Darstellung eines zweiten Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Abrisshammers,
• 14: eine schematische Darstellung eines dritten Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Abrisshammers,
• 15: Ausführungsbeispiele für eine vibrationsentkoppelte Lagerung der erfindungsgemäßen Umschaltvorrichtung mit druckbelasteten Dämpfungselementen in Form von Gummidämpfern,
• 16: Ausführungsbeispiele für eine vibrationsentkoppelte Lagerung der erfindungsgemäßen Umschaltvorrichtung mit zugbelasteten Dämpfungselementen in Form von Gummidämpfern,
• 17: Ausführungsbeispiele für eine vibrationsentkoppelte Lagerung der erfindungsgemäßen Umschaltvorrichtung mit druckbelasteten Dämpfungselementen in Form von Federdämpfern,
• 18: Ausführungsbeispiele für eine vibrationsentkoppelte Lagerung der erfindungsgemäßen Umschaltvorrichtung mit zugbelasteten Dämpfungselementen in Form von Federdämpfern,
• 19: eine schematische Darstellung eines vierten Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Bohrhammers,
• 20: eine schematische Darstellung eines fünften Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Winkelschleifers,
• 21: eine schematische Darstellung eines sechsten Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Industriestaubsaugers und
• 22: eine schematische Darstellung eines siebten Ausführungsbeispiels des erfindungsgemäßen, elektrischen Bearbeitungsgeräts in Form eines Rasenmähers.

Show it

• 1 : a schematic representation of a first exemplary embodiment of an electrical processing device according to the invention in the form of a hand-held impact wrench,
• 2 : a schematic representation of a first exemplary embodiment of an electric motor according to the invention with a stator tooth carrying four windings,
• 3 : a schematic representation of a second exemplary embodiment of the electric motor according to the invention with a stator tooth carrying two windings,
• 4 : a circuit diagram of an embodiment of the electric motor according to the invention for a parallel connection of the four windings of a stator pole and a delta connection of the three phases of the electric motor,
• 5 : a circuit diagram of an embodiment of the electric motor according to the invention for a series connection of the four windings of a stator pole and a star connection of the three phases of the electric motor,
• 6 : a block diagram of an embodiment of the switching device according to the invention for the electric motor according to FIG 3 until 5 ,
• 7 : an exploded drawing of the electric motor according to the invention with an electromechanical switching device according to the invention,
• 8th : Exemplary embodiments of the electromechanical switching device according to the invention with a rotatable support,
• 9 : Exemplary embodiments of the electromechanical switching device according to the invention with a displaceable carrier,
• 10 : further exemplary embodiments for a displaceable carrier of the electromechanical switching device according to the invention,
• 11 : another embodiment of a rotatable support of the electromechanical switching device according to the invention,
• 12 : a schematic block diagram for the electrical processing device according to the invention,
• 13 : a schematic representation of a second embodiment of the electrical processing device according to the invention in the form of a demolition hammer,
• 14 : a schematic representation of a third exemplary embodiment of the electrical processing device according to the invention in the form of a demolition hammer,
• 15 : Exemplary embodiments for a vibration-decoupled mounting of the switching device according to the invention with pressure-loaded damping elements in the form of rubber dampers,
• 16 : Exemplary embodiments for a vibration-decoupled mounting of the switching device according to the invention with tensile-loaded damping elements in the form of rubber dampers,
• 17 : Exemplary embodiments for a vibration-decoupled mounting of the switching device according to the invention with pressure-loaded damping elements in the form of spring dampers,
• 18 : Exemplary embodiments for a vibration-decoupled mounting of the switching device according to the invention with tensile-loaded damping elements in the form of spring dampers,
• 19 : a schematic representation of a fourth embodiment of the electrical processing device according to the invention in the form of a hammer drill,
• 20 : a schematic representation of a fifth exemplary embodiment of the electrical processing device according to the invention in the form of an angle grinder,
• 21 : a schematic representation of a sixth embodiment of the electrical processing device according to the invention in the form of an industrial vacuum cleaner and
• 22 : a schematic representation of a seventh embodiment of the electrical processing device according to the invention in the form of a lawnmower.

Description of the exemplary embodiments

1 shows an example of an electrical processing device 10 designed as an impact wrench with a three-phase electric motor 12. The impact wrench has a housing 14 with a handle 16 and a tool holder 18 and can optionally be powered and/or powered mechanically and electrically via appropriately designed electromechanical interfaces 19 for mains-independent power supply positively detachable with a battery pack 20 or connected to the mains-dependent power supply via a mains cable 22 with a power supply system, not shown but known to those skilled in the art. In the present example, the power grid has a first supply voltage U _H of 230 V AC (50 Hz) and the battery pack 20 has a significantly different second supply voltage U _L of 36 V DC than the first supply voltage. However, the invention can also be applied with particular advantage to electrical processing devices with rechargeable batteries and mains supplies of other voltage and power classes. In addition, it should be pointed out that the invention is neither limited to rotary impact wrenches nor to hand-held power tools in general, but—as already mentioned—can be used with different mains-independent and/or mains-dependent electrical processing devices.

The electric motor 12 , which is supplied with power by the battery pack 20 or via the mains cable 22 , together with a gear 24 and an impact mechanism 26 are arranged in the housing 14 , for example. The electric motor 12 can be actuated via a main switch 28, i.e. it can be switched on and off and its speed and/or torque can be changed. Alternatively, the electric motor 12 and the transmission 24 can also be arranged in a common sub-housing or in separate motor and transmission housings, which in turn are accommodated in the housing 14 . Impact mechanism 26 is driven via a motor shaft 30 of electric motor 12 and is designed, for example, as a rotary impact mechanism that generates high-intensity abrupt angular momentum and transmits it to tool holder 18, which is used to exchangeably accommodate an insert tool 32. Since the tool holder 18 and the insert tool 32 as such are irrelevant to the invention, they will not be discussed in any more detail. The possible configurations are well known to those skilled in the art.

The electric motor 12 is acted upon by a power bridge 34 of power electronics 36 with a pulse width modulated motor voltage U _M . For this purpose, the power bridge 34 has various power transistors (eg bipolar transistors, field effect transistors, IGBT, or the like) which, depending on the design of the electric motor 12, can be connected eg as an H bridge, B6 bridge or the like. An electronic control or regulation system 38 controls the individual power transistors of the power bridge 34 in accordance with a signal specified by the main switch 28 in order to generate the PWM voltage U _M . Since the person skilled in the art is familiar with the different possible configurations of the power bridge 34 and the control or regulating electronics 38, they will not be discussed in any more detail. The control or regulation electronics can be designed, for example, as a microcontroller, DSP, ASIC or the like.

Regarding 2 the three-phase electric motor 12 includes an internal rotor 40 and an external stator 42 with three stator poles 44. Each stator pole 44 ^I , 44 ^II , 44 ^III has in the exemplary embodiment shown M=2 stator teeth 46, which are diametrically opposite over the circumference of the stator 42 to distribute. Each stator tooth 46 ^I , 46 ^II in turn has a plurality N=4 windings 48 for driving the rotor 40 . The individual windings 48 ^I , 48 ^II , 48 ^III , 48 ^IV can differ in their type, ie in the number of turns, in their cross section and/or in their material. However, they can also be designed in the same way. In order to magnetize the stator 42 and thus cause the rotor 40 to rotate, a current I _n flows through the N=4 windings 48 of the corresponding stator tooth 46 ^I , 46 ^II of the stator pole 44 ^I , 44 ^II , 44 ^III . The magnetic fields B _n produced in this way are proportional to the currents I _n and the number of turns of the individual windings 48. Thus, a winding with few turns and a high cross section through which a high current flows can produce the same magnetic field as a Winding with many turns and a small cross-section through which a significantly lower current flows. The individual magnetic fields B _n in the stator tooth 46 ^I , 46" finally add up to form a total magnetic field B=Δn ₌₁ ^N B _n that drives the rotor 40 .

coming back on 1 the electrical processing device 10 can be operated by an operator either with the first supply voltage U _H of 230 V AC (50 Hz) or with the second supply voltage U _L of 36 V DC, which is significantly different from the first supply voltage. Electric motor 12 is switched over between operation with the first supply voltage U _H and operation with the second supply voltage U _L in such a way that a switching device 50 in power electronics 36 switches the N = 4 windings 48 of a stator tooth 46 of electric motor 12 for operation with the first supply voltage U _H or the second Versor supply voltage U _L in series and/or in parallel. With M * N series-connected identical windings 48 of a stator pole 344 ^I , 44 ^II , 44 ^III , the electric motor 12 can thus be operated with (M * N) times the supply voltage compared to M * N parallel-connected windings 48, while in parallel operation a (M * N) times the total current can flow compared to the series connection. The switching device 50 can be configured electronically or electromechanically. This is explained below in connection with the 6 until 11 even more detailed.

Switching between the operating modes of the electric motor 12 can take place either manually by means of an operating mode switch 52 that can be actuated by the operator and/or automatically by means of a sensor system 54 of the electrical processing device 10 . The control or regulating electronics 38 of the electrical processing device 10 can evaluate a request signal from the operating mode switch 52 or the sensor system 54 for switching between the operating modes of the electric motor 12 and control the switching device 50 for parallel and/or series connection of the corresponding windings 48. If the switching device 50 is constructed electromechanically, it is alternatively also conceivable that the operating mode switch 52 is mechanically coupled to the switching device 50 and adjusts it directly.

The request signal can be generated, for example, via a cover flap 56 for a mains connection 58 of the electrical processing device 10 . This is closed during battery operation and open during mains operation as a result of an inserted mains plug 60 of the mains cable 22 . The position of the cover flap 56 is detected by means of the sensors 54, for example in the form of a reed contact or microswitch, and the corresponding request signal for operation with the first supply voltage U _H is sent to the control or regulating electronics 38. Operation with the first supply voltage U _H has priority over operation with the second supply voltage U _L despite the inserted battery pack 20 . Alternatively, it is also conceivable that the power supply with the highest performance has priority. For this purpose, the power electronics 36 is divided into first power electronics 36 _H for operation with the first supply voltage U _H and at least one second power electronics 36 _L for operation with the at least one second supply voltage U _L . In a particularly advantageous manner, the two electronic power units _36H , _36L are electrically isolated from one another. This will be discussed in more detail later with reference to 12 To be received. In order to protect the operator from voltage surges from exposed and live electrical contacts on the one hand and the electrical processing device 10 from short circuits caused by exposed contacts on the other hand, it is also provided that in the case of mains operation the electrical contacts of the unused electromechanical interface 19 for the battery pack 20 and in the case of battery operation, the electrical contacts of the unused mains connection 58 of the electrical processing device 10 are electrically isolated. This galvanic separation can be effected by switching elements of the switching device 50 (not shown in detail) which, in the case of an electromechanical configuration of the switching device 50, have corresponding clearances and creepage distances. Alternatively or in addition, it is also possible to mechanically cover the respective unused connections 19 or 58 . In the case of battery operation, for example, the cover flap 56 of the mains connection 58 can be locked electromechanically or use of the electrical working device 10 can only be released when the cover flap 56 is locked. Correspondingly, a locking of the electromechanical interface 19 for the battery pack 20 is conceivable, in which case it could also be sufficient here to cover only the individual electrical contacts of the interface 19, for example with sliding plastic caps or the like.

The generation of the request signal or the detection of the desired operating mode can be implemented in various other ways. For example, it could also be done using a human-machine interface (HMI) in the form of a control panel or a touch display on the electrical processing device 10, which the operator has to actuate accordingly. Such an HMI can also serve as a display for the operating mode set using the switching device 50 . Of course, the switching device 50 itself can also have a corresponding display, for example in the form of an LED or the like. In addition or as an alternative, control via an app via a wireless interface via WLAN, Bluetooth or the like on the electrical processing device 10 would be conceivable. A switch or button on the power cord 22 would also be possible. Other solutions for switching the operating mode of electric motor 12 could be an RFID tag on power cord 22, direct sensing of the supply voltage in electrical processing device 10, e.g. using a step-up and/or step-down converter, or coding in battery pack 20 be realised. In the event that both the mains cable 22 and the battery pack 20 are connected to the electrical processing device 10, the power supply with the highest capacity (very powerful battery packs sometimes have a higher current delivery capacity than a supply from the mains) or basically the mains voltage have priority. A corresponding setting of the priorities can be made in an app, for example. Furthermore, it is also possible to switch automatically between the two operating modes if, for example, the mains supply breaks off when the battery pack 20 is plugged in or, conversely, an inserted battery pack 20 has been largely discharged.

Safety features are also conceivable, such as an automatic or manual switchover to mains operation when the electrical processing device 10 is being transported with one or more battery packs 20 inserted. an automatic switchover takes place in the event of a longer period of non-use by means of a movement or acceleration sensor integrated in the electrical processing device 10 . If the electrical processing device 10 is transported with several battery packs 20 connected in series (e.g. 2 x 18 V), galvanic isolation of the individual battery packs 20 is also conceivable in order to comply with the corresponding transport standards, since each battery pack 20 is then regarded as an individual battery pack . An automatic switchover from battery to mains operation can also be provided if the temperature of one of the plugged-in battery packs 20 suddenly rises, in particular when the electrical processing device 10 is being supplied with power by a plurality of battery packs 20 connected in series. The same is conceivable if there is an abrupt voltage drop in the at least one second supply voltage U _L , or if it lies outside a permissible voltage range.

• • U_H = 230 V AC (ca. 300 V DC), U_L = 12 V DC → M * N = 25 Wicklungen 48
• • U_H = 230 V AC (ca. 300 V DC), U_L = 18 V DC (max. ca. 20 V) → M * N = 15 Wicklungen 48
• • U_H = 230 V AC (ca. 300 V DC), U_L = 36 V DC (max. ca. 40 V) → M * N ≅ 8 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 12 V DC → M * N ≅ 12 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 18 V DC (max. ca. 20 V) → M * N ≅ 8 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 36 V DC (max. ca. 40 V) → M * N ≅ 4 Wicklungen 48

Since the switching device 50 with respect to 2 which connects the N=4 windings 48 of a stator tooth 46 ^I , 46 ^II in series during operation with the first supply voltage U _H or in mains operation flows through the M*N=8 windings 48 of a stator pole 344 ^I , 44 ^II , 44 ^III Identical configuration in each case the same current I ₁ = I ₂ = ... = I _MN . There is an overall low current requirement and B=B ₁ +B ₂ . . . +B _MN =M*N*B ₁ applies to the overall magnetic field. In the case of operation with the second supply voltage U _L or in the case of battery operation, the parallel connection of the M*N=8 windings 48 results in an addition of their individual currents I ₁ +I ₂ + . . . +I _MN . If each of the 8 windings 48 is of the same type, this results in a total current I=8*I ₁ , which results in the total magnetic field being B=8*B ₁ again. Consequently, the electric motor 12 has essentially the same maximum power in both operating modes. Depending on the level of the first and the second supply voltage U _H , U _L , a different number of the M * N windings 48 of a stator pole 44 ^I , 44 ^II , 44 ^III can be connected in parallel and/or in series with essentially the same maximum power of the electric motor 12 . This then enables so-called multi-voltage operation of the electric motor 12 according to the invention or a multi-voltage device for mains, battery or hybrid operation, ie for example battery operation with 12, 18 or 36 and/or mains operation with 120 or 230 V, without the number having to adapt the stator teeth 46 in the electric motor 12 . From this, the following number M * N of windings 48 per phase U, V, W or stator pole 344 ^I , 44", 44 ^III can be determined, for example, with the voltage ratio of the rectified, first supply voltage U _H and the second supply voltage U _L can be rounded off, since the electric motor 12 generally tolerates smaller supply voltage differences:

• • U _H = 230 V AC (approx. 300 V DC), _UL = 12 V DC → M * N = 25 windings 48
• • U _H = 230 V AC (approx. 300 V DC), _UL = 18 V DC (max. approx. 20 V) → M * N = 15 windings 48
• • U _H = 230 V AC (approx. 300 V DC), _UL = 36 V DC (max. approx. 40 V) → M * N ≅ 8 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 12 V DC → M * N ≅ 12 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 18 V DC (max. approx. 20 V) → M * N ≅ 8 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 36 V DC (max. approx. 40 V) → M * N ≅ 4 windings 48

For the best possible concentricity and correspondingly optimized symmetry properties of the electric motor 12, it is expedient to distribute the number of windings 48 evenly over the M stator teeth 46 of the stator poles 44. If, for example, each stator pole 44 ^I , 44", 44 ^III M = 2 stator teeth 46, the number of windings 48 per stator pole 344 ^I , 44", 44 ^III should be an integer divisible by M, e.g. in the case of 2 stator teeth 46 per stator pole 344 ^I , 44", 44 ^III 26 instead of 25 and 16 instead of 15 windings 48.

For operation with the second supply voltage U _L , it can be additionally provided, for example, that the switching device 50 connects the windings 48 of a stator pole 344 ^I , 44 ^II , 44 ^III in parallel in such a way that in the case of a small maximum current, a smaller number J < M * N Windings 48 are connected in parallel than in the case of a maximum current that is significantly higher than the small maximum current. Correspondingly, for operation with the first supply voltage U _H J <M*N, windings 48 can be connected in series in order to be able to operate the electric motor 12 with different mains voltages. It is also possible for the switching device 50 to switch at least part of the M*N windings 48 of a stator pole 344 ^I , 44 ^II , 44 ^III for operation with at least one Intermediate voltage U _Z is connected in parallel and in series, the intermediate voltage U _Z being between the at least one first supply voltage U _H and the at least one second supply voltage U _L .

In 3 A further embodiment of the electric motor 12 according to the invention is shown, in which the switching between operation with the first supply voltage U _H and operation with the at least one second supply voltage U _L takes place in such a way that the switching device 50 for operation with the first supply voltage U _H a first winding 48 ^I of a stator tooth 46", in particular a winding 48 with a high number of turns and a small cross section, and for operation with the at least one second supply voltage U _L a second winding 48" of the stator tooth 46", in particular a winding 48 with small number of turns and a large cross section. The second winding 48" is wound over the first winding 48 ^I in a particularly advantageous manner. This enables a dual-voltage device for hybrid operation to be implemented in a simple and cost-effective manner with a "high-voltage winding" 48 ^I , which is designed, for example, for mains operation with typically 300V DC, and a "low-voltage winding" 48 ^II , which designed for battery operation with 36 V. Here, too, the windings 48 can be designed in such a way that the electric motor 12 can be operated in both operating modes with essentially the same maximum power. Likewise, more than two windings 48 per stator tooth 46 ^I , 46 "and fewer or more than two stator teeth 46 per stator pole 44 ^I , 44 ^II , 44 ^III are conceivable. The invention can also be used for very small or fast-rotating electric motors 12 with only one Stator tooth 46 per stator pole 344 ^I , 44", 44 ^III (simple three-phase EC motors) are applied.

• • U_H = 230 V AC (ca. 300 V DC), U_L = 12 V DC → M * N ≅ 14 Wicklungen 48
• • U_H = 230 V AC (ca. 300 V DC), U_L = 18 V DC (max. ca. 20 V) → M * N ≅ 9 Wicklungen 48
• • U_H = 230 V AC (ca. 300 V DC), U_L = 36 V DC (max. ca. 40 V) → M * N ≅ 4 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 12 V DC → M * N ≅ 7 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 18 V DC (max. ca. 20 V) → M * N ≅ 4 Wicklungen 48
• • U_H = 120 V AC (ca. 150 V DC), U_L = 36 V DC (max. ca. 40 V) → M * N ≅ 2 Wicklungen 48

4 shows the connection of the three phases U, V, W of the electric motor 12 controlled by the power bridge 34 by PWM signal with windings 48 of the three stator poles 44 connected in parallel in a delta connection. The two windings 48 of the stator teeth 46 of each stator pole 344 ^I , 44", 44 ^III (cf. also 3 ) grouped together. In 5 is different from 4 a star connection of the phases U, V, W, each with series-connected windings 48 of the three stator poles 44 of the electric motor 12. The possibility of being able to operate the electric motor 12 not only with windings 48 connected in parallel or in series, but also with phases U, V, W connected in a delta or star connection, means that the electrical processing device 10 can be used very universally for small direct voltages up to high AC voltages in connection with simple to design and inexpensive power electronics 36 or switching device 50 are possible. Furthermore, the use of all windings 48 of the electric motor 12 for the different operating modes allows a reduced weight of the electric motor 12 with a simultaneous increase in effectiveness. The optional connection of the phases U, V, W as a star or delta connection in connection with the star connection results in a significant reduction in the current requirement by a factor of 1.73 (root 3) per phase U, V, W or stator pole 44 ^I , 44 ^II , 44 ^III , which is particularly advantageous when the electric motor 12 starts up, while high currents and outputs can be used in the delta connection. Taking the above explanations into account, the following reduced number M*N of windings 48 per phase U, V, W or stator pole 44 ^I , 44 ^II , 44 ^III can be determined as an example for the star connection:

• • U _H = 230 V AC (approx. 300 V DC), _UL = 12 V DC → M * N ≅ 14 windings 48
• • U _H = 230 V AC (approx. 300 V DC), _UL = 18 V DC (max. approx. 20 V) → M * N ≅ 9 windings 48
• • U _H = 230 V AC (approx. 300 V DC), _UL = 36 V DC (max. approx. 40 V) → M * N ≅ 4 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 12 V DC → M * N ≅ 7 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 18 V DC (max. approx. 20 V) → M * N ≅ 4 windings 48
• • U _H = 120 V AC (approx. 150 V DC), _UL = 36 V DC (max. approx. 40 V) → M * N ≅ 2 windings 48

For operation with the first supply voltage U _H , it is expedient to connect all windings 48 of a stator pole 344 ^I , 44", 44 ^III in series in addition to the star connection. Additionally or alternatively, it may be expedient for operation with the second supply voltage U _L be to switch all windings 48 of a stator pole 344 ^I , 44 ^II , 44 ^III in parallel in addition to the delta connection Since all windings 48 of the stator 42 are always supplied with current at the same time, the electric motor 12 can be used in this way with optimum utilization of the installation space and a minimum number of windings on the one hand with a star connection of the phases U, V, W for the first supply voltage U _H and with a delta connection of the phases U, V, W for the second supply voltage U _L. The electric motor 12 can be operated with particular advantage in battery mode with the at least Do not switch a second supply voltage U _L to a star connection, but only with a delta connection maintain phases U, V, W. Thus, all windings 48 are supplied with a lower motor voltage U _M than in mains operation with the first supply voltage U _H and the electric motor 12 runs at reduced power. This then allows, for example, a soft start of the electric motor 12 of an electrical processing device 10 designed as a rotary hammer to generate the most effective impact energy possible. Likewise, this procedure can also enable a warm-up, reduced operation for replaceable battery packs 20 with reduced performance (eg due to aging) or reduced power consumption when idling. It can also be provided that when the windings 48 are switched between operation with the first supply voltage U _H and the second supply voltage U _L , the electric motor 12 operates with essentially the same Maximum power is operable.

In connection with the possibility of a soft start and a correspondingly high number N of windings 48 per stator tooth 46 ^I , 46", of which not all windings 48 are then permanently energized, a so-called booster operation can also be implemented in which the switching device 50 all windings 48 of the stator teeth 46 are briefly energized simultaneously for operation with the at least one first supply voltage U _H and for operation with the at least one second supply voltage U _L in order to achieve significantly higher motor power to cover power peaks is additionally or alternatively according to the embodiment 2 also possible in pure battery operation with the at least one second supply voltage U _L . Depending on the situation, the windings 48 of a stator tooth 46', 46" can, depending on the state of charge of the battery or battery pack 20 - when the state of charge is low, the available second supply voltage U _L is also low - and the load - a higher load current I causes a higher voltage drop and so that a higher second supply voltage U _L can be switched in series and/or in parallel very quickly (virtually in real time) by means of an electronically designed switching device 50. With a high load and a low state of charge of the rechargeable battery or rechargeable battery pack 20, a winding mix with a higher Parallel connection component and with a low load and high state of charge with a lower parallel connection component advantageous.

Booster operation can also be implemented in such a way that at least one of the windings 48 of a stator tooth 46 ^I , 46" is additionally energized only for this purpose and otherwise remains without current for battery and mains operation in the normal power range.

6 shows a first embodiment of the switching device 50 according to the invention for the electric motor 12 with three phases U, V, W and stator poles 44, wherein analogously to the 3 until 5 each stator pole 344 ^I , 44", 44 ^III M=2 stator teeth 46, each with N=2 windings 48. Each winding 48', 48" of the electric motor 12 is connected to the switching device 50 via two electrical contact points 62. In the exemplary embodiment shown, a total of 3*8=24 contact points 62 are therefore required between the three-phase electric motor 12 and the switching device 50 . For the sake of clarity, in 6 only the phase U or the stator pole 44' is shown in detail within a schematic box ^64I . The two remaining phases V and W or stator poles 44 ^II , 44 ^III are designed accordingly and are therefore only shown as empty boxes 64 ^II and 64 ^III . The electrical contact points 62 between the electric motor 12 and the switching device 50 can be embodied as plug connections, crimp connections, screw connections, soldered connections or welded connections (cf. 7 ).

Switching device 50 has a plurality of first switching elements 66 for series connection of windings 48 of stator teeth 46 and a plurality of second switching elements 68 for parallel connection of windings 48 of stator teeth 46 for each phase U, V, W or stator pole 44 ^I , 44 ^II , 44 ^III . In this case, for each stator pole 44 ^I , 44", 44 ^III with M stator teeth 46 and N windings 48 per stator tooth 46 ^I , 46" for series connection and/or for parallel connection of the total of M * N stator windings 48 M * N - 1 first switching elements 66 and M * (2N - 1) second switching elements 68 are provided. In a three-phase stator 42 with three stator poles 44, M = 2 stator teeth 46 per stator pole 44 ^I , 44 ^II , 44 ^III and N = 2 windings 48 per stator tooth 46 ^I , 46", this results in 44 ^I , 44 ^II per stator pole , 44 ^III 2 * 2 - 1 = 3 first switching elements 66 and 2 * (4 - 1) = 6 second switching elements 68. In total, the switching device 50 therefore has 3 * (3 + 6) = 27 first and second switching elements 66, 68 For the series connection of the windings 48, the first switching elements 66 of the switching device 50 are closed and the second switching elements 68 are opened, while for the parallel connection of the windings 48 in the reverse manner the first switching elements 66 are opened and the second switching elements 68 are closed a series connection of the windings 48 before.

In order to be able to additionally connect the phases U, V, W of the electric motor 12 or its stator poles 44 in a star or delta connection, a third switching element 70 and a fourth switching element 72 are also provided for each stator pole 344 ^I , 44", 44 ^III The third switching elements 70 are closed and the fourth switching elements 72 are opened for the star connection of the phases U, V, W, while the third switching elements 70 are opened for the delta connection of the phases U, V, W and the fourth switching elements 72 are closed. In the exemplary embodiment shown, there is therefore a delta connection in addition to the series connection of the windings 48, ie one opposite to the 4 and 5 further switching variant of the invention. For a three-phase electric motor 12 with M = 2 stator teeth 46 per stator pole 344 ^I , 44", 44 ^III and N = 2 windings 48 per stator tooth 46 ^I , 46", the total is 27 + 6 = 33 first, second, third and fourth switching elements 66, 68, 70, 72 for the switching device 50. Without the additional switchover option from a delta to a star connection, 1.73 times as many windings 48 would be necessary according to the above statements, ie N=in the present example 4 instead of 2 windings 48 per stator tooth 46 ^I , 46". Thus, instead of the 33 first, second, third and fourth switching elements 66, 68, 70, 72, then a total of 3 * ((M * N - 1) + M * ( 2N−1))=63 first and second switching elements 66, 68 are required for the switching device 50, with the third and fourth switching elements 70, 72 then being omitted switching elements the switching device 50 and thus also to further space, weight and cost savings.

For activating a series connection of all windings 48 of a stator pole 44 ^I , 44", 44 ^III in connection with a star connection of the phases U, V, W according to 5 then all first and third switching elements 66, 72 are closed and all second and fourth switching elements 68, 72 are opened. For activating a parallel connection of all windings 48 of a stator pole 44 ^I , 44 ^II , 44 ^III in combination with a delta connection of the phases U, V, W according to 4 all second and fourth switching elements 68, 72 are closed and all first and third switching elements 66, 70 are opened. This can be done simultaneously or with particular advantage to avoid short circuits with a dead time T of a few nanoseconds up to a few seconds between the switching processes of the first and second switching elements 66, 68 or third and fourth switching elements 70, 72.

In order to also be able to operate the electric motor 12 in countries with slightly different first supply voltages U _H (e.g. Japan, Australia, etc.), a switchable load 74 is provided for each stator pole 344 ^I , 44", 44 ^III in the case of a star connection. This is connected between the fourth switching element 72 and a ground potential GND of the switching device 50 in such a way that it can only act when the fourth switching element 72 of the switching device 50 is closed the load 74 can be deactivated and activated by opening the further switching element 76. With an activated star connection and load 74, it is thus possible in a very simple manner to implement mains operation with 240 V instead of 230 V or with 120 V instead of 110 V. A Recognition of the respective first supply voltage U _H can correspond, for example, to a de mechanical or electrical coding, an RFID tag or the like on the power cord 22 done. Switching by the operator using the operating mode switch 52 or an HMI of the electrical processing device 10 or, in contrast to this, a fixed specification that can only be changed by the manufacturer is also conceivable.

In a further embodiment, the switching device 50 has at least one additional switching element (not shown) for switching over two position and/or speed sensors 78 _H , 78 _L for the rotor 40 of the electric motor 12 depending on the operation of the electric motor 12 with the first supply voltage U _H or with the at least one second supply voltage U _L (cf. 2 ). It is thus possible to adapt the position and/or speed sensors 78 _H , 78 _L in a particularly simple manner to the control or regulating electronics 38 or the power electronics 36 _H , 36 _L controlled by them for the correct operation of the electric motor 12 . This is necessary because there are typically different sensor positions of the individual sensors for the power electronics 36 _H , 36 _L for the first and the at least one second supply voltage U _H , U _L . As a rule, the three Hall sensors of the position and/or speed sensors 78 _H for the power electronics 36 _H are distributed differently over the circumference of the rotor 40 than the three Hall sensors of the position and/or speed sensors 78 _L for the Power electronics 36 _L . It is also conceivable to use one of the three Hall sensors of the position and/or speed sensors 78 _H , 78 _L together for the power electronics 36 _H , 36 _L so that only five Hall sensors are required in total. It is also possible to use the same three Hall sensors for both power electronics _36H , _36L . However, in this case too, switching by means of the switching device 50 is advantageous for the reliable operation of the respective power electronics 36 _H , 36 _L. The position and/or speed sensors 78 _H , 78 _L are preferably switched over when the electric motor 12 is not in operation, for example to secure the clearance or creepage distances between the mains and battery supply or to avoid EMC interference.

All switching elements of switching device 50 can be designed as semiconductor switches, in particular as MOSFETs, field effect transistors, IGBTs, bipolar transistors, or the like be. Relays are also conceivable. Depending on the load capacity and switching speed requirements, however, mixed forms are also possible in which, for example, the first and second switching elements 66, 68 are designed as semiconductor switches and the third and fourth switching elements 70, 72 and the further switching elements 76 are designed as relays.

As already mentioned above, the switching over, in particular of the first, second, third and fourth switching elements 66, 68, 70, 72 of the switching device 50, takes place by means of the control or regulating electronics 38 integrated in the electrical processing device 10, depending on the operating mode switch 52 or of the sensor system 54. At the same time, the control or regulating electronics 38, depending on the main switch 28, activate the power bridge 34 in order to apply the PWM voltage U _M to the windings 48 of the individual phases U, V, W. The switching device 50 is therefore circuitry between the power bridge 34 and the electric motor 12. As below in connection with 7 until 11 is still explained, the switching device 50 can alternatively also be designed electromechanically with corresponding switching elements designed as switching contacts. A mixed form of semiconductor switches and electromechanical switching contacts is also conceivable. For example, the first and second switching elements 66, 68 required for the series and/or parallel connection of the windings 48 and the switching elements required for the position and/or speed sensors 78 can be designed as electromechanical switching contacts and those for the star or delta connection of the phases U, V, W necessary third and fourth switching elements 70, 72 as well as the further switching elements 76 necessary for the country-specific grid adjustment can be designed as semiconductor switches.

In 7 is an exploded view of the electric motor 12 according to the invention with the rotor 40, the stator 42, an adapter ring 80 on the stator side and the electromechanically designed switching device 50 according to the invention. In order to enable an electric motor 12 which is as compact as possible and easy to replace, the switching device 50 is designed as a modular assembly of the electric motor 12 which is constructed along an axis defined by the motor shaft 30 of the electric motor 12 . The rotor 40 has a plurality of permanent magnets 82 which are connected to the motor shaft 30 in a torque-proof manner. A fan 84 for cooling the electric motor 12 and, if applicable, the power electronics 36 of the electrical processing device 10 is also connected in a torque-proof manner to the motor shaft 30. The rotor 40 and the motor shaft 30 are connected by means of a bearing 86, which can be designed, for example, as a ball or roller bearing can, stored in the stator 42. The stator 42 in turn has the windings 48 distributed over its inner circumference on the stator teeth 46 (cf. also the 2 and 3 ). The stator 42 is surrounded by a pole pot 88 designed as a laminated core.

The switching elements 66, 68, 70, 72, 76 of the switching device 50 are connected to the windings 48 of the stator poles 44 by means of the electrical contact points 62 formed on the adapter ring 80 as contact pins 90 and on the switching device 50 as contact sockets 68 (not shown in detail). or stator teeth 46 can be reversibly connected to a side of the electric motor 12 facing away from the motor shaft 30 . For this purpose, the electrical contact points 62 are each distributed in a ring on the adapter ring 80 and arranged on an outer circumference of the switching device 50 . The manufacturer can therefore very easily attach the switching device 50 to the adapter plate 80 of the stator 42 and remove it again if necessary. The contact pins 90 are in turn permanently soldered, crimped or welded to the windings 48 of the stator 42 . The contact sockets 92 of the switching device 50 can be connected in one piece to the switching elements 66, 68, 70, 72, 76 via copper tracks in the sense of a stamped grid or also via soldered, crimped or welded connections. Instead of a reversible plug-in connection between switching device 50 and adapter ring 80, it is alternatively also conceivable for the electrical contact points 62 between switching device 50 and adapter ring 80 or the windings 48 to be permanently soldered or welded. A direct crimp or screw connection of the windings 48 to the switching elements 66, 68, 70, 72, 76 or the electrical contact points 62 of the switching device 50 is also possible.

The electromechanical switching device 50 is constructed in two parts. It consists of a pot-shaped housing part 94 and a cover 96 which is designed as a rotatable operating mode switch 52 in the exemplary embodiment shown. The electrical contact points 62 designed as contact sockets 92 are arranged in a ring in the pot-shaped housing part 94 and are connected to the connections of the switching elements 66, 68, 70, 72, 76, for example by punched tracks, cables or conductor tracks of a printed circuit board. The connections of the switching elements 66, 68, 70, 72, 76 can be designed, for example, as contact slides or contact springs 98, which consist of a copper alloy such as CuSn6 or are designed as sandwich springs consisting of spring steel with a copper layer and slide over corresponding contact tracks 100 ( cf. also 9 ).

In 8a are referring to 6 three first and six second switching elements 66, 68 on an outer circular path and three third and three fourth switching elements 70, 72 on an inner circular path of a designed as a plate-shaped printed circuit board 102 carrier 104 is arranged. The contact sliders 98 of the switching elements 66, 68, 70, 72, shown only as dots for better clarity, slide on the arcuate contact tracks 100, which are designed, for example, as copper tracks of the printed circuit board 102 and which, for better and more permanent electrical conductivity, each have a gold-plated, silver-plated, tinned, galvanized or nickel-plated surface coating. This applies in the same way to the surfaces of the contact sliders 98. The first and second switching elements 66, 68 and the third and fourth switching elements 70, 72 each share a contact slider 98 as a common electrical contact point 62 (cf. also 6 ). Only when both contact sliders 98 of a switching element 66, 68, 70, 72 have electrical contact with a contact track 100 is the respective switching element 66, 68, 70, 72 electrically closed; otherwise it is open. In 8a Therefore, in the shown position of the circuit board 102, the second and fourth switching elements 68, 72 are closed to generate a parallel connection of the windings 48 of a stator pole 344 ^I , 44", 44 ^III in connection with a delta connection of the phases U, V, W of the electric motor 12 (see. 4 ), while the first and third switching elements 66, 70 are open. It should be noted that the in 8a Although the circuit board 102 shown can switch all three phases U, V, W, it can only switch the windings 48 of a single stator pole 44 ^I. Consequently, the switching device 50 for the windings 48 of the two other stator poles 44 ^II , 44 ^III must either have two further circuit boards 102, which are constructed in accordance with the circuit board 102 shown and are arranged adjacent to the first circuit board 102, but no contact tracks 100 on the inner circular path carry more for the third and fourth switching elements 70, 72, or which has the additionally required three first and six second switching elements 66, 68 per phase V, W or stator pole 44", 44 ^III on two further circular paths. The individual contact paths 100 must also be designed in their arc length and positioning in such a way that no faulty switching states arise for the desired operating modes Correspondingly, clearances or creepage distances 106 are provided on the printed circuit board 102 adjacent to the contact tracks 100 to generate the dead time T between the switching processes.

The at least one printed circuit board 102 is indirect (for example via a linkage, transmission or the like) or according to 8b directly operatively connected to the operating mode switch 52 in that turning the operating mode switch 52 by the operator in the direction of rotation R causes the first and third switching elements 66, 70 to close and the second and fourth switching elements 68, 72 to open in order to produce a series connection of the windings 48 of a stator pole 44 ^I , 44", 44 ^III in connection with a star connection of the phases U, V, W (cf. 5 ). Subsequent turning back counter to the direction of rotation R then again leads to opening of the first and third switching elements 66, 70 and closing of the second and fourth switching elements 68, 72 to produce a parallel connection of the windings 48 of a stator pole 344 ^I , 44", 44 ^III in conjunction with a delta connection of the phases U, V, W. Since - as described above - the first and second switching elements 66, 68 and the third and fourth switching elements 70, 72 are each switched in a complementary manner to one another, the clearances or creepage distances 106 serve to Avoidance of short circuits due to unintentional simultaneous closing states of the first and second or third and fourth switching elements 66, 68 or 70, 72.

Alternatively, it is also conceivable that the first and second switching elements 66, 68 for parallel or series connection of the windings 48 of all three stator poles 44 are arranged on a first plate-shaped circuit board 102 and the switching device 50 is a second plate-shaped circuit board that can be rotated independently of the first circuit board 102 Circuit board 102 with the third and fourth switching elements 70, 72 for optional delta or star connection of the three phases U, V, W or stator poles 44 has. In this way, the windings 48 and the phases U, V, W can be connected independently of one another by means of a correspondingly two-part operating mode switch 52 . In an analogous manner, the further switching elements 76 for the switchable load 74 for adapting the first supply voltage U _H to national conditions and/or the switching elements for switching over the position and speed sensors 78 (cf. 2 ) be realized.

8b shows a section through the switching device 50 according to FIG 8a , the housing part 94 and the cover 96 designed as an operating mode switch 52 also being shown. The contact tracks 100 interacting with the contact sliders 98 are arranged on their respective circular tracks on one side of the printed circuit board 102 . Only three contact tracks 100 and two contact sliders 98, which cause the second and fourth switching elements 68, 72 to close, are visible in the sectional view. The printed circuit board 102 is directly operatively connected to the operating mode switch 52, so that turning the operating mode switch 52 by the operator also directly causes the printed circuit board 102 to turn. As already to 8a indicated, also more to the first circuit board 102 adjacent circuit boards Switching device 50 to be operatively connected to the mode switch 52.

In 8c another section through the switching device 50 is shown. In contrast to the embodiment according to 8a the circuit board 102 is now printed on both sides with the contact tracks 100 for the switching elements 66, 68, 70, 72. Depending on the requirements of the electric motor 12, a plurality of such printed circuit boards 102 can of course also be used here for switching over the windings 48 of the stator poles 44 and the phases U, V, W.

9 shows two further exemplary embodiments of the switching device 50 in a perspective detail for the first and second switching elements 66, 68. These also apply as an example to the other switching elements of the switching device 50. In contrast to 8th the carrier 104 embodied as a printed circuit board 102 is now displaceably arranged along a displacement direction R. Correspondingly, circuit board 102 also interacts with a sliding operating mode switch 52 (not shown) for switching over first and second switching elements 66, 68 in such a way that sliding operating mode switch 52 results in complementary opening and closing of first and second switching elements 66, 68 by the the circuit board 102 printed contact tracks 100 causes. Instead of a displaceable operating mode switch 52, a rotatable operating mode switch 52 can also be used in conjunction with a correspondingly designed linkage, which transforms the rotary movement into a linear movement.

While in accordance with the neckline 9a the printed circuit board 102 with the contact tracks 100 and the contact sliders 98 arranged on both sides of the circuit board 102 are printed on the edges, resulting in a total of two first and two second switching elements 66, 68, it is in 9b only a first and a second switching element 66, 68 due to the one-sided printing of the contact tracks 100 and the one-sided arrangement of the contact slides 98. By printing the printed circuit board 102 on both sides with a corresponding number of contact slides 98, however, more switching elements can also be implemented here, each of which in horizontal direction are formed. As already in 8th shown, can also be in 9 implement a dead time T for switching the operating modes by means of appropriately designed clearances or creepage distances 106 next to the contact tracks 100 .

In the 10 and 11 further embodiments of the carrier 104 of the switching device 50 are shown. On the individual components with identical references as in the previous ones 8th and 9 , will not be discussed further because of their identical mode of action. the 10 is intended to clarify in particular that a prism 108 ( 10a) , a cuboid 110 ( 10b) or a U-profile 112 ( 10c ) with appropriately positioned contact tracks 100 in question, with analog 9 an opening and closing of the first and second switching elements 66, 68 is effected by a linear displacement of the carrier 104. In 11 the carrier 104 is designed as a rotatable roller 114, in particular for the switching elements 76 for activating and deactivating the load 74 (cf. 6 ) educated. 11b shows a section through the in 11a roller 114 shown in perspective. Other possible carrier shapes would be a truncated cone, a sphere or the like.

All of the configurations of the electromechanical switching device 50 can also be combined with one another. A combination of an electromechanical and an electronic switching device 50 consisting of semiconductor switches or relays is also conceivable in the electrical processing device 10 . Instead of a printed circuit board 102 with printed contact tracks 100, the contact tracks 100 can also be designed as a stamped grid, which is encapsulated with a plastic and which then itself forms the pot-shaped housing part 94.

In 12 A schematic representation of the electrical processing device 10 is shown. The electrical processing device 10 can be topologically divided into a predominantly mechanical driven part 116 beyond a topological dividing line 118 and a supply and drive part 120 on this side of the topological dividing line 118. "On this side" should be the side facing the electrical supply and "beyond" should be the the machining of a workpiece facing side of the electrical processing device 10 are understood. "This side" is therefore to be regarded as functionally before and "beyond" as functionally behind the topological dividing line 118 . In particular, the driven part 116 is often designed specifically for the area of application of the electrical processing device 10 and can therefore, in contrast to the supply and drive part 120, generally not be produced and used universally for different types of electrical processing devices.

Essential components of the stripping part 116 are the gear 24 and a special output mechanism 122 for the respective application of the electrical processing device 10. Under the stripping part 116 should therefore be understood as a mechanism that uses the drive energy of the electric motor 12 to use the elec rian processing device 10 mechanically converts. An example of an output mechanism 122 of the output part 116 would be in the description 1 mentioned impact mechanism 26 including tool holder 18 and application tool 32 of the rotary impact wrench shown there. However, the drive mechanism 122 can also be formed by the chassis of a vehicle, the grinder of a food processor, the device for generating and guiding the air flow of a fan or the like.

Components of supply and drive part 120 that are essential to the invention are power electronics 36, which have switchover device 50, and electric motor 12. Control or regulating electronics 38, which actuate power electronics 36, and any other components of electrical processing device 10 are shown here for the sake of clarity be dispensed with. The power electronics 36 is divided into the first power electronics 36 _H for operation with the first supply voltage U _H and the at least one second power electronics 36 _L for operation with the at least one second supply voltage U _L , with the first supply voltage U _H being generated, for example, by a national Mains power (indicated by the socket) is provided, while the at least one second supply voltage U _L is supplied by the battery pack 20 . Thus, the first electronic power system 36 _H is embodied as an AC electronic system and the at least one second electronic power system 36 _L is embodied as a DC electronic system. The two power electronics units _36H , 36L are _preferably electrically isolated from one another in order to avoid voltage flashovers between them. Common to both electronic power systems 36 _H , 36 _L is the power bridge 34 for controlling the electric motor 12 via the switching device 50 using the PWM voltage U _M . The switching device 50 is located within the electrical processing device 10 on this side of the topological dividing line 118 between the electric motor 12 and the power bridge 34. As described above, it can be designed as a modular assembly of the electric motor 12 or as a mechanically separate assembly from the electric motor 12 on another Point in the electrical processing device 10 are located. A division of the switching device 50 into an electronic and an electromechanical part or into several electromechanical or electronic parts within the electrical processing device 10 is possible.

The battery pack 20 is with reference to 1 designed as a removable battery pack. A rechargeable battery or rechargeable battery pack 20 permanently integrated in the electrical processing device 10 is also conceivable. A mixed form of integrated battery and exchangeable battery pack is also possible. In addition, several exchangeable battery packs 20 electrically connected in series or in parallel can be used on the electrical processing device 10 . Depending on the operating mode or the first supply voltage U _H or the second supply voltage U _L , the switching device 50 then activates the first or the second electronic power system 36 _H , 36 _L .

13 shows a further exemplary embodiment of an electrical processing device 10 in the form of a demolition hammer. A significant difference to the impact wrench according to 1 consists in the configuration of the predominantly mechanical driven part 116 in the energy supply of the demolition hammer with two battery packs 20. In the case of two battery packs 20 connected in series, each with 18 V, this results in a second supply voltage U _L of 36 V DC. In contrast to the impact wrench according to 1 the electric motor 12 can be assigned to a significantly higher performance class, but without being based on the in 12 described, topological division of the electrical processing device 10 in the driven part 116 and the supply and drive part 120 changes somewhat. A detailed description of the driven part 116 of the demolition hammer with the driven mechanism 122 and the tool holder 18 together with the insert tool 32 is omitted here, since this is of secondary importance for the invention.

Switching between the operating modes of the electric motor 12 can be carried out as in the first exemplary embodiment 1 either manually by an operator or automatically by means of a sensor system 54 of the electrical processing device 10 . In addition to the sensor system 54 for detecting the position of the cover flap 56 for the mains cable 22 or its connector plug 60, the operator can also switch the operating mode of the electric motor 12 using the operating mode switch 52, an HMI, an app or the like.

In 14 the demolition hammer is off 13 shown in another embodiment. The switching device 50 of the power electronics 36, which is designed in particular electromechanically, is arranged separately from the electric motor 12 in the housing 14 of the demolition hammer. The operating modes can be switched over by the operator using the operating mode switch 52 . Furthermore, the first power electronics 36 _H are designed for operation with the first supply voltage U _H , in particular with a mains voltage, and the second power electronics 36 _L are designed for operation with the second supply voltage U _L , in particular with a battery voltage, as well as the power bridge 34 integrated therein for Control of the electric motor 12 with the PWM voltage U _M as a separate unit from the switching device 50 in Housing 14 provided. For this purpose, both the switching device 50 and the rest of the power electronics 36 each have separate sub-housings 124 which are in turn connected to the housing 14 in a fixed or integral manner. To isolate the switching device 50 or the entire power electronics 36 from any heavily vibrating components of the demolition hammer during operation, the output mechanism 122 and the electric motor 12 together with the gear 24 are mounted in the housing 14 by means of at least one damping element 126. In this way it is possible to protect the power electronics 36 or the switching device 50 from damage to the corresponding components and the electrical contacts. A spring in the form of a spiral, leaf or torsion spring, for example, which is arranged between the housing 14 and the output mechanism 122, the transmission 24 and/or the electric motor 12, can be used as the damping element 126. Rubber dampers or the like or at least one damping actuator controlled by the closed-loop or open-loop control electronics 38 (not shown) are also conceivable as damping elements 126 .

As an alternative or supplement to the vibration decoupling of the housing 14 from the output mechanism 122 and/or the electric motor 12, provision can also be made for the switching device 50 itself to be decoupled from the housing 14. This is based on different embodiments according to the following 15 until 18 be illustrated, the switching device 50 being designed as an electronic switching device 50 with the sub-housing 124 . It is also possible that, in the case of an electromechanical switching device 50 , the modular assembly consisting of the housing part 94 and the cover 96 designed as an operating mode switch 52 is mounted in the housing 14 of the electrical processing device 10 in a vibration-decoupled manner. The switching device 50 can also be arranged in the housing 14 at a defined angle that is not equal to 0 or 180° to the electric motor 12 . Vibration-decoupled mounting of the modular assembly together with the electric motor 12 in the housing 14 is also conceivable.

In 15a the switching device 50 arranged in the sub-housing 124 is mounted in a vibration-decoupled manner on corresponding holding elements 130 of the housing 14 for accommodating the rubber buffers 128 via damping elements 126 embodied essentially as square rubber buffers 128 . Where is on the left side of 15a shown a top view and on the right side a side view. The sub-housing 124 is therefore mounted in the housing 14 via a total of eight rubber buffers 128 and eight retaining elements 130 . Vibrations of the housing 14 can thus be sufficiently dampened to protect the switching device 50 from damage during the operation of the electrical processing device 10 . 15b shows the plan view of a second possible embodiment of the damping elements 126 as a polygonal rubber buffer 128 with at least one internal air chamber 132. In 15c a third exemplary embodiment of the damping element 126 is shown as a substantially barrel-shaped rubber buffer 130 with corresponding lateral air chambers 132 that completely encloses the sub-housing 124 at least in one direction. With particular advantage, the switching device 50 can be easily plugged into this rubber buffer 130 with its sub-housing 124 . As well in 15b as well as in 15c Retaining elements 130 are provided on the housing 14, the shape of which is adapted in a complementary manner to the shape of the damping elements 126 for the best possible fixation and storage.

16 shows further embodiments of the damping element 126 for the switching device 50. In 16a For example, the damping element 126 is designed as a stamped rubber foil 134, which is stretched over four retaining elements 130, designed as eyelets or domes 136, of the housing 14 and which supports the sub-housing 124 of the switching device 50 in a quasi-hanging manner. For this purpose, the sub-housing 124 has a projection 138 which engages through an opening in the rubber film and which is fixed to the rubber film 134 via six corresponding retaining elements 140 . In 16b the damping element 126 is designed as a rubber ring 142 which is mounted on the housing 14 via four eyelets or domes 136 and which carries the sub-housing 124 of the switching device 50 via four retaining elements 140 designed as hooks. 16c shows another possible embodiment of the rubber foil 134 16a , which is now only mounted on two eyelets or domes 136 in the housing 14 . In contrast to 15 , where the at least one damping element 126 exerts a compressive force F on the subhousing 124 or the switching device 50, it is in 16 a pulling force F

In the 17 and 18 the damping elements 126 are designed as springs, with in 17 analogous to 15 a compressive force F and in 18 analogous to 16 a tensile force F acts on the sub-housing 124 of the switching device 50 . In the 17a , 17b and 17c the damping elements 126 are each designed as leaf springs 144, as spiral springs 146 and as leg fenders 148 which, depending on the design, interact with correspondingly designed holding elements 130, 140 on the housing 14 of the electrical processing device 10 or on the sub-housing 124 of the switching device 50. the 18a and 18b each show a tension spring 150 and damping element 126 designed as a bending or torsion spring 152, which is mounted vibration-decoupled on the one hand on eyelets or domes 136 of the housing 14 and on the other hand on specially designed holding elements 140 of the sub-housing 124.

In the 19 until 22 further exemplary embodiments of an electrical processing device 10 are shown. The electrical processing device is 10 in 19 a hammer drill with an output mechanism 122 designed as a pneumatic impact mechanism and, for example, a tool holder 18 designed as an SDS drill chuck for an application tool 32 designed as an SDS drill. The gear 24 driven by the motor shaft 30 of the electric motor 12 is also specially designed for use with the hammer drill designed. The same applies to the in 20 angle grinder shown, the in 21 illustrated industrial vacuum cleaner and in 22 illustrated lawn mower. Here, too, the output part 116 is in each case specially adapted to the intended use of the electrical processing device 10, without wanting to go into further detail in the following, since this is of secondary importance for the invention as such. At this point, however, it should be pointed out again that the invention can also be used in many other electric motor-driven processing devices with at least two different supply voltages, such as kitchen appliances, construction machinery, vehicles, airplanes, ships, etc.

the 19 until 22 illustrate accordingly 13 a topological division of the respective electrical processing device 10 into the predominantly mechanical driven part 116 beyond the topological dividing line 118 and the supply and drive part 120 on this side of the topological dividing line 118. The switching device 50 within the housing 14 of the electrical processing device 10 is always topologically different from that Abtriebspart 116 separated that it is functional, in particular as part of the power electronics 36, arranged in front of the electric motor 12 and the driven part 116. What is also common to each electrical processing device 10 is that the power electronics 36 are divided into first power electronics 36 _H , in particular AC electronics, for operation with the first supply voltage U _H and in at least one second power electronics 36 _L , in particular DC electronics, for operation with the at least one second supply voltage U _L , the first and the at least one second power electronics 36 _H , 36 _L being electrically isolated from one another. In addition, the switching device 50 is always arranged in the housing 14 on a side of the electric motor 12 which is remote from the motor shaft 30 .

the inside 19 The rotary hammer shown differs significantly in terms of its application and the driven part 116 designed for it from the one shown in 13 demolition hammer shown, but what both have in common is roughly the power class and the energy supply via two battery packs 20. Thus, both electrical processing devices 10 can each have a very similar supply and drive part 120. Accordingly, the electric motor 12 together with the switching device 50 or the complete power electronics 36 can be used with particular advantage as a modular assembly in both electrical processing devices 10, which makes the manufacture and maintenance of the electrical processing devices 10 significantly easier and more cost-efficient. The same also applies to other electrical processing devices 10 of similar performance classes, such as the one in 21 shown industrial vacuum cleaner and the in 22 lawn mower shown or the one in 1 impact wrench shown and the in 20 shown small angle grinder.

It should finally be pointed out that the exemplary embodiments shown neither on the 1 until 22 is still limited to the stated voltage values and/or the absolute number of rechargeable batteries or rechargeable battery packs 20 and the switching elements of the switching device 50 . In addition, all exemplary embodiments can alternatively be implemented with a classic DC motor, depending on the performance and cost requirements. Both the rechargeable batteries 20 and the electronics for charging management can either be integrated directly in the electrical processing device 10 or connected to the electrical processing device 10 externally via a cable.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3316453 A1 [0003]
• US 2019/0229599 A1 [0004]

Claims (18)

Electric motor (12) with a rotor (40) and a stator (42), the stator (42) having three stator poles (44) and each stator pole (44 ^I , 44 ^II , 44 ^III ) having an integer multiple of stator teeth (46). each has a plurality of windings (48) for driving the rotor (40), the windings (48) of the stator teeth (46) being designed in terms of their type and/or number such that the electric motor (12) has three phases (U , V, W) can be operated optionally with a first supply voltage (U _H ), in particular for mains operation, or with at least one second supply voltage (U _L ), which is significantly different from the first supply voltage (U _H ), in particular for battery operation, characterized characterized in that all windings (48) of a stator tooth (46 ^I , 46 ^II ) can be connected in series and/or in parallel for operation with the first supply voltage (U _H ) or the at least one second supply voltage (U _L ) and that the phases (U, V, W) as Star connection or delta connection can be switched. Electric motor (12) after claim 1 , characterized in that for operation with the first supply voltage (U _H ) all the windings (48) of a stator pole (44 ^I , 44", 44 ^III ) are connected in parallel and the phases (U, V, W) are connected in a delta circuit. Electric motor (12) according to one of the preceding claims, characterized in that for operation with the at least one second supply voltage (U _L ) all the windings (48) of a stator pole (44 ^I , 44 ^II , 44 ^III ) are connected in series and the phases ( U, V, W) are connected in a star connection. Electric motor (12) according to one of the preceding claims, characterized in that the number of windings (48) of a stator pole (44 ^I , 44", 44 ^III ) essentially depends on the ratio of the first and the at least one second supply voltage (U _H , U _L ) and can be further reduced by a factor of 1.73, particularly in the case of star connection of the phases (U, V, W). Electric motor (12) according to one of the preceding claims, characterized in that the electric motor (12) when switching the windings (48) between operation with the first and the at least one second supply voltage (U _H , U _L ) both with a star connection and can also be operated with phases (U, V, W) connected in a delta connection, in particular with essentially the same maximum power. Switching device (50) for controlling the windings (48) of an electric motor (12) according to one of the preceding Claims 1 until 5 , characterized in that by means of the switching device (50) the windings (48) of the stator teeth (46) of the electric motor (12) for operation with the first supply voltage (U _H ) or the at least one second supply voltage (U _L ) in series and /or the phases (U, V, W) of the electric motor (12) can be switched in parallel and in addition as a star connection or as a delta connection. Switching device (50) after claim 6 , characterized by a plurality of first switching elements (66) for series connection of the windings (48) of the stator teeth (46) and a plurality of second switching elements (68) for parallel connection of the windings (48) of the stator teeth (46). Switching device (50) after claim 7 , characterized in that for each stator pole (44 ^I , 44 ^II , 44 ^III ) of the electric motor (12) with M stator teeth (46) and N windings (48) per stator tooth (46 ^I , 46 ^II ) M * N - 1 first switching elements (66) for series connection and M * (2N - 1) second switching elements (68) for parallel connection of the M * N windings (48) are provided. Switching device (50) according to any one of the preceding Claims 7 or 8th , characterized in that for the series connection of the windings (48) the first switching elements (66) are closed and the second switching elements (68) are open, and in that for the parallel connection of the windings (48) the first switching elements (66) are open and the second switching elements ( 68) are closed. Switching device (50) according to any one of the preceding Claims 7 until 9 , characterized in that a third and a fourth switching element (70, 72) is provided for the star or delta connection of the phases (U, V, W) of the electric motor (12) for each stator pole (44 ^I , 44", 44 ^III ). Switching device (50) after claim 10 , characterized in that for the star connection of the phases (U, V, W) the third switching elements (70) are closed and the fourth switching elements (72) are open and for the delta connection of the phases (U, V, W) the third switching elements (70) opened and the fourth switching elements (72) are closed. Switching device (50) according to any one of the preceding Claims 6 until 11 , characterized in that each stator pole (44 ^I , 44", 44 ^III ) of the electric motor (12) has a further switching element (76) is provided for series connection with a switchable load (74). Switching device (50) according to any one of the preceding Claims 6 until 12 , characterized by further switching elements for switching over a position and/or speed sensor system (78 _H , 78 _L ) for the rotor (40) of the electric motor (12) depending on the operation of the electric motor (12) with the first supply voltage (U _H ) or with the at least one second supply voltage (U _L ). Switching device (50) according to any one of the preceding Claims 6 until 13 , characterized in that the switching elements (66, 68, 70, 72) are designed as semiconductor switches, in particular as MOSFETs, field effect transistors, IGBTs, bipolar transistors or the like, or as relays. Switching device (50) according to any one of the preceding Claims 6 until 14 , characterized in that the switching device (50) is a modular assembly (94, 96) of the electric motor (12). Electrical processing device (10), in particular a hand-held power tool, with an electric motor (12) according to one of the preceding Claims 1 until 5 and a switching device (50) according to any one of the preceding Claims 6 until 15 . Electrical processing device (10) after Claim 16 , characterized in that it has control or regulating electronics (38) for controlling the switching device (50). Electrical processing device (10) after Claim 17 , characterized in that the control or regulating electronics (38) switches the first and the second as well as the third and the fourth switching elements (66, 68, 70, 72) each with a dead time (T).

Images